Octreotide Research Articles

NGIWY-Amide: A Bioinspired Ultrashort Self-Assembled Peptide Gelator for Local Drug Delivery Applications.

Fibrillar structures derived from plant or animal origin have long been a source of inspiration for the design of new biomaterials. The Asn-Gly-Ile-Trp-Tyr-NH2 (NGIWY-amide) pentapeptide, isolated from the sea cucumber Apostichopus japonicus, which spontaneously self-assembles in water to form hydrogel, pertains to this category. In this study, we evaluated this ultra-short cosmetic bioinspired peptide as vector for local drug delivery applications. Combining nuclear magnetic resonance, circular dichroism, infrared spectroscopy, X-ray diffraction, and rheological studies, the synthesized pentapeptide formed a stiff hydrogel with a high β-sheet content. Molecular dynamic simulations aligned well with scanning electron and atomic-force microscopy studies, revealing a highly filamentous structure with the fibers adopting a helical-twisted morphology. Model dye localization within the supramolecular hydrogel provided insights on the preferential distribution of hydrophobic and hydrophilic compounds in the hydrogel network. That was further depicted in the diffusion kinetics of drugs differing in their aqueous solubility and molecular weight, namely, doxorubicin hydrochloride, curcumin, and octreotide acetate, highlighting its versatility as a delivery vector of both hydrophobic and hydrophilic compounds of different molecular weight. Along with the observed cytocompatibility of the hydrogel, the NGIWY-amide pentapeptide may offer new approaches for cell growth, drug delivery, and 3D bioprinting tissue-engineering applications.

A case of aHUS with successful treated refractory hypertension for renin-angiotensin inhibitor, ischemic colitis for octreotide acetate

A case of aHUS with successful treated refractory hypertension for renin-angiotensin inhibitor, ischemic colitis for octreotide acetate

Octreotide-conjugated silver nanoparticles for active targeting of somatostatin receptors and their application in a nebulized rat model

Abstract Drug uptake and distribution through cell–receptor interactions are of prime interest in reducing the adverse effects and increasing the therapeutic effectiveness of delivered formulations. This study aimed to formulate silver nanoparticles (AgNPs) conjugated to somatostatin analogs for specific delivery through somatostatin receptors (SSTRs) expressed on cells and by nebulizing the prepared AgNPs formulations into lung cells for in vivo application. AgNPs were prepared using the citrate reduction method, yielding AgNPs–CTT, which was further chemically conjugated to octreotide (OCT) to form AgNPs–OCT through an amide linkage. The AgNPs–OCT formulation was coated using alginate to yield a carrier, AgNPs–OCT–Alg, feasible for drug delivery through nebulization. AgNPs were uniform in size with an acceptable range of zeta potential. Furthermore, the concentrations of AgNP formulations were found safe for the model cell lines used, and cell proliferation was significantly reduced in a dose-dependent manner (p < 0.05). In the healthy lung tissues, AgNPs–OCT–Alg accumulated at a concentration of 0.416 ± 5.7 mg/kgtissue, as determined via inductively coupled plasma optical emission spectrometry. This study established the accumulation of AgNPs, specifically the AgNPs–OCT–Alg, in lung tissues, and substantiated the active, specific, and selective targeting of SSTRs at pulmonary sites. The anticancer efficacy of the formulations was in vitro tested and confirmed in the MCF-7 cell lines. Owing to the delivery suitability and cytotoxic effects of the AgNPs–OCT–Alg formulation, it is a potential drug delivery formulation for lung cancer therapy in the future.

Pectin microparticles for peptide delivery: Optimization of spray drying processing

Spray-dried pectin microparticles can potentially improve the oral bioavailability of peptides by virtue of their mucoadhesion. However, developing such formulations with desirable quality attributes is challenging due to the sensitivity of microparticle critical quality attributes towards changes in spray drying processing parameters. In this study, a central composite design approach was applied to investigate the influence of input temperature, aspirator rate, feed flow rate, polymer concentration and polymer feed weight on the yield and particle size of pectin microparticles prepared via spray drying. A mathematical model for the prediction of yield was statistically significant with good predictability. A maximum yield of 72.2% was achieved through optimizing the spray drying conditions. The particle size remained in a relatively narrow range (D50, 2.16–3.67 μm), and therefore was considered independent of the factors investigated. The model for yield prediction was further validated using octreotide acetate as a representative peptide. The presence of octreotide acetate in the pectin microparticles increased their surface roughness and decreased their melting enthalpy. In addition, it was determined that pectin with a high degree of esterification (72%, AU201) resulted in faster drug release compared to pectin with a lower degree of esterification (62%, CU401). Interestingly, the degree of esterification did not impact microparticle particle size, morphology or thermal properties. This study demonstrates the importance of DoE in optimization of the spray drying process for the development of pectin-based peptide microparticles. This is the first report using spray-dried pectin-based microparticles for octreotide delivery. The yield prediction model achieved using a central composite design may also be helpful for formulation development of similar drug products.

Octreotide ameliorates hypoxia/reoxygenation-induced cerebral infarction by inhibiting oxidative stress, inflammation and apoptosis, and via inhibition of TLR4/MyD88/NF-κB signaling pathway

Purpose: To explore the effects of octreotide (OCT) on oxidative stress, inflammation and apoptosis in hypoxia/reoxygenation (H/R)-induced cerebral infarction.Methods: The in vitro model of cerebral infarction was established by treating N2A cells with hypoxia for 4 h and reoxygenation for 24 h. The viability of N2A cells was determined by CCK-8 assay. The cells were divided into 3 groups: control group, H/R group, and H/R+OCT group. The cells in H/R+OCT group were pretreated with OCT (60 ng/mL) before H/R treatment. The oxidative stress of N2A cells were assessed by determining the levels of superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT), reactive oxygen species (ROS) and malondialdehyde (MDA). Inflammation of N2A cells was evaluated by evaluating the levels of TNF-α, IL-1β, IL-6, and IL-8, while the apoptosis of N2A cells was assessed by flow cytometry. Western blot analysis was used to determine the expression of Bcl-2, Bax, TLR4, MyD88, and NF-κB.Results: Octreotide treatment significantly reduced the level of oxidative stress. The inflammation of N2A cells caused by hypoxia/reoxygenation was inhibited by treatment with octreotide. Apoptosis of N2A cells was also inhibited by octreotide treatment. Hypoxia/reoxygenation activated TLR4/MyD88/NF-κB signaling pathway, while octreotide inhibits the activation of this pathway.Conclusion: The results reveal that octreotide inhibits hypoxia/reoxygenation-induced oxidative stress,as well as the inflammation, and apoptosis of N2A cells by inhibiting TLR4/MyD88/NF-κB signaling pathway. Thus, these findings may provide new insights into the treatment of cerebral infarction.

Recessive RYR1-related centronuclear myopathy with congenital chylothorax in a Japanese male child

Abstract Introduction: The severity of RYR1-related centronuclear myopathy (CNM) is typically intermediate between the most severe X-linked myotubular myopathy and mildly severe DNM2-related centronuclear myopathy. We report a Japanese male patient with recessive RYR1-related CNM that was exceedingly severe compared to previously reported cases and had congenital chylothorax, which is a very rare complication of congenital myopathy. Patient concerns: A male neonate from non-consanguineous Japanese parents presented with generalized hypotonia and respiratory distress at birth. Diagnosis: Muscle biopsy of the vastus lateralis showed typical features of CNM. The next-generation sequencing assay detected RYR1 gene mutations, which were c.5989G>A (p.E1997K) and c.1441-2A>G. These findings confirmed the diagnosis of recessive RYR1-related CNM. Chest radiography showed bilateral pleural effusions at birth, which was diagnosed as chylothorax on laboratory examination. Interventions: Mechanical ventilation and tube feeding were initiated. Chylothorax was managed with drainage and treatment with octreotide acetate. Outcomes: His clinical course was so rapidly progressive that he could not move his fingers even when he was one year of age. Conclusion: Congenital chylothorax with congenital myopathy can be considered an indicator of a severe phenotype, and its presence may indicate poor prognosis.

Novel Platform for Predicting Drug Effects in Patients with Acromegaly: Translational Exposure-Response Evaluation of Growth Hormone-Inhibitory Effect of Octreotide after Growth Hormone-Releasing Hormone Stimulation.

Acromegaly is a chronic systemic disease characterized by facial and peripheral changes caused by soft tissue overgrowth and is associated with multiple comorbidities. Despite available surgical and medical therapies, suitable treatments for acromegaly are still lacking. Efficient drug development requires an understanding of the exposure-response (E-R) relationship based on nonclinical and early clinical studies. We aimed to establish a platform to facilitate the development of novel drugs to treat acromegaly. We evaluated the E-R relationship of the growth hormone (GH)-inhibitory effect of the somatostatin analog octreotide under growth hormone-releasing hormone + arginine stimulation in healthy participants and compared the results with historical data for patients with acromegaly. This randomized five-way crossover study included two placebo and three active-treatment periods with different doses of octreotide acetate. GH secretion in the two placebo periods was comparable, which confirmed the reproducibility of the response with no carryover effect. GH secretion was inhibited by low-, medium-, and high-dose octreotide acetate in a dose-dependent manner. We also examined the E-R relationship in monkeys as a preclinical drug evaluation study and in rats as a more convenient and simple system for screening candidate drugs. The E-R relationships and EC50 values were similar among animals, healthy participants, and patients with acromegaly, which suggests that GH stimulation studies in early research and development allowed simulation of the drug response in patients with acromegaly. SIGNIFICANCE STATEMENT: This study demonstrated similar exposure-response relationships in terms of the growth hormone-inhibitory effect of octreotide after growth hormone-releasing hormone stimulation among healthy participants, monkeys, and rats. The research methods and analyses utilized in this study will be useful for simulating the dosages and therapeutic effects of drugs for acromegaly and will facilitate the research and development of novel therapeutic agents with similar modes of action.

Impact of octreotide counterion nature on the long-term stability and release kinetics from an in situ forming depot technology

The generation of acylated impurities has represented an important hurdle in the development of long acting injectables for therapeutic peptides using biocompatible polymers with a polyester moiety. We investigated here an in situ forming depot (ISFD) technology that uses polyethylene glycol - polyester copolymers and a solvent exchange mechanism to promote depot formation. This technology has shown promise in formulating small molecules as well as therapeutic proteins. In the present work, using the well-known somatostatin analog octreotide acetate (OctAc) as a model molecule, we evaluated this delivery platform to release therapeutic peptides. Peptide acylation was found to be pronounced in the formulation, while it was very limited once the depot was formed and during the release process. The octreotide acylation pattern was fully characterized by LC-MS/MS. Moreover, it was demonstrated that exchanging the acetate anion with more hydrophobic counterions like pamoate or lauryl sulfate allowed to greatly improve the peptide stability profile, as well as the formulation release performance. Finally, the in vivo evaluation through pharmacokinetics studies in rat of these new octreotide salts in ISFD formulations showed that octreotide was quantifiable up to four weeks post-administration with a high bioavailability and an acceptable initial burst.

Development and characterization of composition-equivalent formulations to the Sandostatin LAR® by the solvent evaporation method.

Sandostatin long-acting release® (SLAR) is a long-acting injectable somatostatin analogue formulation composed of octreotide encapsulated in glucose-initiated poly(lactic-co-glycolic acid) (PLGA) microspheres. Despite the end of patent protection, SLAR remains resistant to generic competition likely due to complexity of production process, the uniqueness of the glucose star polymer, and the instability of octreotide in the formulation. Here, we describe development of glucose-PLGA-based composition-equivalent to SLAR formulations prepared by double emulsion-solvent evaporation method and the effect of variations in encapsulation variables on release kinetics and other formulation characteristics. The following encapsulation variables were adjusted at constant theoretical loading of 7.0% peptide: PLGA concentration, pH of inner water phase, and stirring rate. After final drying, the microspheres were examined with and without annealing at 50°C under vacuum for 3days. The loading and encapsulation efficiency (EE) of octreotide acetate, manufacturing yield, and in vitro drug release kinetics in PBStc (10mM phosphate-buffered saline (PBS) with 1% triethyl citrate and 0.02% sodium azide at pH 7.4) were determined by UPLC. The in vitro release and acylation kinetics of octreotide for the solvent evaporation formulations prepared were similar to SLAR although the initial burst was slightly higher. Key formulation steps identified to maximize microsphere yield and minimize residual solvent and initial burst release included (a) addition of acetic acid to the peptide before preparation and (b) annealing the microspheres under vacuum after drying. Controlled release octreotide formulations prepared and investigated in this study could provide a better understanding of the effect of production variables on release performance and supply information useful for making progress in manufacturing of SLAR generic equivalents.

P-194 Study of efficacy and safety of combination of octreotide acetate LAR with lenvatinib as second-line therapy in patients with advanced G1-G2 NETs of non-pancreatic origin

There is a documented role of tyrosine kinase inhibitors e.g. sunitinib, axitinib, etc. in grade 2 NET. Lenvatinib is a multikinase inhibitor which includes inhibition of VEGFR-1,2,3, platelet-derived growth factor receptor α (PDGFRα), KIT and RET, as well as FGFR1-4. The aim of this study was to assess the efficacy and toxicity of lenvatinib and octreotide acetate LAR combination in patients with advanced G1-2 extra-pancreatic NETs.

Long-term effects of somatostatin analogues in rat GH-secreting pituitary tumor cell lines

PurposeFirst-generation somatostatin analogs, octreotide (OCT) and lanreotide, are the cornerstone for the medical treatment of growth hormone (GH)-secreting pituitary tumors. A new multireceptor analog, such as pasireotide (PAS), showed better activity than OCT in long-term treatment of patients with acromegaly, but modulation of intracellular key processes is still unclear in vitro. In this study, we evaluated the antitumor activity of OCT and PAS in two GH-secreting pituitary tumor cell lines, GH3 and GH4C1, after a long-term incubation.MethodsThe effects of PAS and OCT on the cell viability, cell cycle, apoptosis, GH secretion, and tumor-induced angiogenesis have been evaluated through a colorimetric method (MTS Assay), DNA flow cytometry with propidium iodide, and Annexin V-FITC/propidium iodide staining, ELISA assay and zebrafish platform, respectively.ResultsPAS showed a more potent antitumor activity compared to OCT in GH3 cell line exerted through inhibition of cell viability, perturbation of cell cycle progression, and induction of apoptosis after 6 days of incubation. A concomitant decrease in GH secretion has been observed after 2 days of incubation only with PAS. No effect on tumor-induced angiogenesis has been reported after treatment with OCT or PAS in zebrafish/tumor xenograft model.ConclusionLong-term incubation with PAS showed a more potent antitumor activity than that reported after OCT in GH3 cells, mainly modulated by a cell cycle perturbation and a relevant induction in apoptosis.

Acromegaly with empty sella syndrome.

SummaryAcromegaly is a rare, chronic progressive disorder with characteristic clinical features caused by persistent hypersecretion of growth hormone (GH), mostly from a pituitary adenoma (95%). Occasionally, ectopic production of GH or growth hormone-releasing hormone (GHRH) with resultant GH hypersecretion may lead to acromegaly. Sometimes localizing the source of GH hypersecretion may prove difficult. Rarely, acromegaly has been found in patients with an empty sella (ES) secondary to prior pituitary radiation and/or surgery. However, acromegaly in patients with primary empty sella (PES) is exceeding rarely and has only been described in a few cases. We describe a 47-year-old male who presented with overt features of acromegaly (macroglossia, prognathism, increased hand and feet size). Biochemically, both the serum GH (21.6 μg/L) and insulin-like growth factor 1 (635 μg/L) were elevated. In addition, there was a paradoxical elevation of GH following a 75 g oral glucose load. Pituitary MRI demonstrated an ES. In order to exclude an ectopic source of GH hypersecretion, further biochemical tests and imaging were done, which were unremarkable. Notably, increased uptake in the sella turcica on the 68Gallium DOTATATE PET/CT confirmed the ES as the likely source of GH secretion. As no overt lesion was noted, medical treatment (octreotide acetate) was initiated with a good clinical and biochemical response. At his 3 month follow-up, he reported an improvement in symptoms (fatigue and headache), however he still complained of low libido. Due to a persistently low testosterone level at follow-up, a long-acting testosterone was initiated. His GH level normalised, and IGF-1 has significantly reduced.Learning pointsThe commonest cause of acromegaly is due to GH hypersecretion from pituitary adenomas (95%).Acromegaly has rarely been found in patients with ES.It is important to exclude a past history suggestive of pituitary apoplexy.Extra-pituitary source of GH such as ectopic production of GHRH with resultant GH hypersecretion needs to be excluded.In such cases, since there is no resectable mass, medical therapy is the primary treatment option.

Lipophilic Salts and Lipid-Based Formulations: Enhancing the Oral Delivery of Octreotide.

Successful oral peptide delivery faces two major hurdles: low enzymatic stability in the gastro-intestinal lumen and poor intestinal membrane permeability. While lipid-based formulations (LBF) have the potential to overcome these barriers, effective formulation of peptides remains challenging. Lipophilic salt (LS) technology can increase the apparent lipophilicity of peptides, making them more suitable for LBF. As a model therapeutic peptide, octreotide (OCT) was converted to thedocusate LS (OCT.DoS2), and compared to the commercial acetate salt (OCT.OAc2) in oral absorption studies and related in vitro studies, including parallel artificial membrane permeability assay (PAMPA), Caco-2, in situ intestine perfusion, and simulated digestion in vitro models. The in vivo oral absorption of OCT.DoS2 and OCT.OAc2 formulated in self-emulsifying drug delivery systems (SEDDS) was studied in rats. LS formulation improved thesolubility and loading of OCT in LBF excipients and OCT.DoS2 in combination with SEDDS showed higher OCT absorption than the acetate comparator in the in vivo studies in rats. The Caco-2 and in situ intestine perfusion models indicated no increases in permeability for OCT.DoS2. However, the in vitro digestion studies showed reduced enzymatic degradation of OCT.DoS2 when formulated in the SEDDS formulations. Further in vitro dissociation and release studies suggest that the enhanced bioavailability of OCT from SEDDS-incorporating OCT.DoS2 is likely a result of higher partitioning into and prolonged retention within lipid colloid structures. The combination of LS and LBF enhanced the in vivo oral absorption of OCT primarily via the protective effect of LBF sheltering the peptide from gastrointestinal degradation.

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Evaluation of the Octreotide Acetate Pen Injector and its Instructions for Use in a Formative Human Factors Study.

IntroductionOctreotide acetate subcutaneous injection is indicated to treat acromegaly and the symptoms of carcinoid tumors and vasoactive intestinal peptide tumors (VIPomas). This formative human factors study assessed the octreotide acetate pen injector and accompanying instructions for use (IFU) with self-trained participants.MethodsThe study enrolled patients with diagnoses of acromegaly, carcinoid tumors, or VIPomas and healthcare practitioners (HCPs) who treat patients with these diagnoses. The IFU provided a stepwise process with illustrations to train participants on using the pen injector. Participants familiarized themselves with the pen injector and the IFU before administering 2 unaided injections into skin-like pads; administering the full dose into the pad was considered a successful injection. The investigators evaluated each injection by performance measures—specific tasks necessary to safely and correctly administer the medication—and subjective measures, which included participant comments, feedback from questions, and suggestions for improvements.ResultsThe study enrolled 11 participants—8 patients and 3 HCPs. Participants had a success rate of 100% for both injections. Errors included 1 participant priming the pen with the incorrect dose and 2 participants not holding the injector button for 10 s after the injection. Neither error led to a failed injection. To improve the IFU, participants suggested changing the order of wording on the priming step, clarifying illustrations of the plunger, and stronger indications to hold the injector button.ConclusionThe octreotide pen injector and IFU were usable by self-trained participants. Participant errors and suggestions provided a foundation for recommendations to improve the IFU.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12325-021-01739-1.

Evaluation of the Octreotide Acetate Pen Injector in a Formative Human Factors Study

Introduction: Subcutaneous injection of octreotide acetate is indicated to treat adults with acromegaly and diarrhea associated with carcinoid tumors or vasoactive intestinal peptide tumors. In this formative human factors study, we evaluated the readability and comprehension of the instructions for use (IFU) and ease of use of the octreotide pen injector. Methods: The study enrolled patients and healthcare practitioners who would be using the pen injector. The IFU contained a stepwise process with illustrations to detail injection administration and safe storage of the octreotide pen injector. Participants read the IFU and familiarized themselves with the device. Participants administered 2 unaided injections into skin-like pads. Injection success was defined as an attempt that delivered the correct dose into the pad. Each injection was evaluated by objective performance and subjective measures. Objective performance measures included assessment of steps necessary to deliver the correct medication dose and ensure user safety. Subjective measures included soliciting participant feedback on perceived success and difficulties administering a dose with the octreotide pen injector, as well as suggestions for improvements. Additional goals included evaluation of the IFU and octreotide pen injector usability aspects. Results: A total of 8 patients and 3 healthcare practitioners enrolled in the study. All (n = 11) participants successfully administered both injections, leading to an overall injection success rate of 100% across twenty-two injections. Subtask errors included participants priming the pen injector with the incorrect dose (n = 1) and not holding the injection button for 10 seconds after the injection (n = 2), but neither error resulted in dosing failure. Participant suggestions for improving the IFU included changes to the illustration of the plunger, reordering statements to clarify the priming process, and detailing how long to let the pen injector come to room temperature. Conclusion: Overall, participants felt the octreotide pen injector was easy to use and the instructions were clearly written and illustrated. Participant feedback and observations by moderators of the study led to recommendations for improvements to the clarity of the IFU.

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PPAR-Alpha Agonist Fenofibrate Combined with Octreotide Acetate in the Treatment of Acute Hyperlipidemia Pancreatitis.

At present, there are more and more patients with acute hypertriglyceridemia pancreatitis in clinical practice. Common treatment measures include fasting and water withdrawal, fluid resuscitation, and somatostatin. In recent years, studies have pointed out that the PPARa agonist fenofibrate may help improve the condition of such patients. Therefore, through clinical research and analysis, we reported for the first time that fenofibrate combined with octreotide acetate has a more excellent effect in the treatment of patients with acute hypertriglyceridemia pancreatitis, and from the perspective of signal pathways, we revealed that the combination of the two drugs has an effect on NF-κB P65. The synergistic inhibitory effect proves that the combined treatment is beneficial to control inflammation, protect liver function, and improve the prognosis of patients. It is worthy of clinical promotion.